import CodeBlock from "@theme/CodeBlock";
import Tabs from "@theme/Tabs";
import TabItem from "@theme/TabItem";

# @farmfe/js-plugin-less
Support `less` for Farm.

## Installation

<Tabs>
  <TabItem value="npm" label="npm">
    <CodeBlock>npm install @farmfe/js-plugin-less less</CodeBlock>
  </TabItem>
  <TabItem value="yarn" label="yarn">
    <CodeBlock>yarn add @farmfe/js-plugin-less less</CodeBlock>
  </TabItem>
  <TabItem value="pnpm" label="pnpm">
    <CodeBlock>pnpm add @farmfe/js-plugin-less less</CodeBlock>
  </TabItem>
</Tabs>

## Usage
```ts {2,6}
import { UserConfig } from '@farmfe/core';
import farmJsPluginLess from '@farmfe/js-plugin-less';

const config: UserConfig = {
  plugins: [
    farmJsPluginLess({ /* options */ })
  ]
}
```

## Options
```ts
export type LessPluginOptions = {
  lessOptions?: Less.Options;
  implementation?: string;
  filters?: {
    resolvedPaths?: string[];
    moduleTypes?: string[];
  };
  additionalData?:
    | string
    | ((context?: string, resolvePath?: string) => string | Promise<string>);
};
```

### lessOptions
Less options. See [less options](https://lesscss.org/usage/#less-options).

Example:
```ts
import path from 'node:path';
import { UserConfig } from '@farmfe/core';
import farmJsPluginLess from '@farmfe/js-plugin-less';

const config: UserConfig = {
  plugins: [
    farmJsPluginLess({
      lessOptions: {
        paths: [path.resolve(process.cwd(), 'styles')]
      }
    })
  ]
}

export default config;
```

### filters
Which files should be processed by `less`. default to `{ resolvedPaths: ['\\.less$'] }` for load and `{ moduleTypes: ['less'] }` for transform.

* `resolvedPaths`: Only files under these paths will be processed. Support regex.
* `moduleTypes`: Only files with these module types will be processed.

`resolvedPaths` and `moduleTypes` are unioned, which means files match any of them will be processed.

Example:
```ts
import { UserConfig } from '@farmfe/core';
import farmJsPluginLess from '@farmfe/js-plugin-less';

const config: UserConfig = {
  plugins: [
    farmJsPluginLess({
      filters: {
        // all files end with .custom-css will be processed
        resolvedPaths: ['\\.custom-less$'],
        moduleTypes: ['less']
      }
    })
  ]
}

export default config;
```

### implementation
`implementation` package name of `less`. Default to `less`.

### additionalData
```ts
type AdditionalDataOption = string | ((content?: string, resolvePath?: string) => string | Promise<string>);
```
Additional data to be added to every less file. Example:
```ts
import { UserConfig } from '@farmfe/core';
import farmJsPluginLess from '@farmfe/js-plugin-less';

const config: UserConfig = {
  plugins: [
    farmJsPluginLess({
      // add variables.less to every less file
      additionalData: `
        @import "./src/styles/variables.less";
      `
    })
  ]
}
```
For less file:
```less title="index.less"
.foo {
  color: @primary-color;
}
```
`additionalData` will be added to the top of the file:
```less title="index.less"
@import "./src/styles/variables.less";

.foo {
  color: @primary-color;
}
```

Function form:
```ts
import { UserConfig } from '@farmfe/core';
import farmJsPluginLess from '@farmfe/js-plugin-less';

const config: UserConfig = {
  plugins: [
    farmJsPluginLess({
      // add variables.less to every less file
      additionalData: (content, resolvePath) => {
        if (resolvePath === '/path/to/index.less') {
          return `
            @import "./src/styles/variables.less";
          `;
        }
      }
    })
  ]
}
```
